Scientific consensus concludes that in the past century, the planet has warmed by several degrees as the result of human activity. For humans, this change may have gone undetected, but for the environment it has not — polar ice caps and glaciers are melting, storms are growing stronger and droughts are lasting longer.

At the same time, humans face obesity as the newest health epidemic. More than one billion adults worldwide are overweight or obese, according to the World Health Organization. And in the United States, 73.7 percent of adults are overweight or obese, according to the Centers for Disease Control.

For author Mark Bittman, food connects these two issues — it is much of the problem, but can also be much of the solution. Poor eating habits have not only led to the nation’s obesity epidemic, but have also contributed to global warming, deforestation and pollution.

In his newest book, “The Food Matters Cookbook: 500 Revolutionary Recipes for Better Living,” Bittman pushes the case for better eating — for the sake of personal health and the natural environment.

The veteran food writer for The New York Times is author of the weekly column “The Minimalist,” which also has a video component. Bittman was never formally trained as a chef, and has never worked in a restaurant. His cooking expertise has come largely from spending time in his kitchen at home.

Unlike other cookbooks, Bittman’s begins with a manifesto on food. He advocates what he calls “sane eating,” consuming mostly plants, few animal products and less junk.

“Sane eating” is the opposite of what most Americans practice. According to Bittman, Americans on average eat 200 pounds of meat each year, in addition to 237 pounds of dairy, and 32 pounds of eggs — totaling 469 pounds of animal products per person, per year.

Moreover, nearly a third of Americans’ calories come from nutrient-poor foods high in sugar, salt and fat. Seven percent of Americans’ calories come from soda alone.

And Bittman knows first hand the value of a plant-based diet. Despite his expertise, he found himself 35 pounds overweight, with high cholesterol and blood sugar, and sleep apnea. This prompted him to change his own diet to a largely plant-based one.

“I follow a strict vegan diet until dinnertime — eating only whole grains, beans, vegetables, fruit, nuts, and seeds. After that I eat whatever I want,” he explains. “That’s my way; your way may be different.”

In addition to the effects on his personal health, Bittman also changed his diet because of its effects on the environment.

Citing statistics from the environmental organization Worldwatch, he says that livestock and their by-products account for nearly half of the world’s greenhouse gas emissions. Consequently, “If each of us ate the equivalent of three fewer cheeseburgers a week, it would have the same impact on the environment as getting rid of all the SUVs in the country.”